The FBI released documents on Monday showing that New York Yankees owner George Steinbrenner had actually worked for them as an informant, including giving his assistance in a terrorism investigation, before he was given a pardon by President Ronald Reagan for illegal campaign contributions.

Several news organizations requested the FBI files on Steinbrenner after his death in July, the first of which was released in December. The documents say he was initially contacted around 1976 or 1977 by the FBI about a “matter of vital interest,” The New York Times reported Tuesday. In 1978, he was contacted again regarding what his lawyer described years later as placing “the lives of his family and himself in jeopardy through being involved in a terrorist matter. He knows he made the right decision because the agents stated this information was very valuable to the United States.”

It is unclear what the “matter” was, because the FBI redacted any specific details about the investigations.

Finally, in 1981, the FBI used Steinbrenner’s assistance again on another undercover probe into a national security case, after which he was praised for his “get involved approach.”

The documents are actually petitions filed by Steinbrenner to receive a pardon for the contributions to the Nixon 1972 re-election campaign. In 1974, he pleaded guilty to conspiracy to funnel corporate campaign funds to politicians, and to making a “false and misleading” explanation of a $25,000 contribution to Nixon’s campaign and influencing workers at his American Shipbuilding Company to lie to a grand jury. At the time he denied all allegations of wrongdoing. Instead of serving jail time, he was forced to pay a $15,000 fine. But he was suspended from Major League Baseball for two years by then-commissioner Bowie Kuhn.

In 1979, Steinbrenner sought a pardon based on his contention that he was advised by his lawyers that the contributions were legal. His attempt at the pardon was denied. “Everybody has dents in his armor,” he told the Times in 1987, admitting his mistakes. “That’s something I have to live with.”

But apparently, the cooperation with the feds helped because as he left office in 1989, President Reagan pardoned Steinbrenner, lifting his conviction. The Yankees did not comment on the development.